Rotatable adjustment knobs, or dials, are commonly used to make adjustments to an adjustable portion of a device such as an optical or electrical device. For example, rotatable dials are commonly used to adjust an elevation setting and a windage setting for a riflescope or other suitable weapon aiming device. Rotatable dials are also used to adjust other features of riflescopes, binoculars, spotting scopes, or other suitable optical device, such as parallax, focus, illumination brightness, or other suitable feature. Other examples of rotatable dials used to adjust an adjustable portion of a device include volume control dials, channel selection dials, and other suitable dials.
The present inventor has recognized that in many applications it would be advantageous for an adjustment knob or dial to automatically lock in place, thus helping ensure that the setting selected by a user remains set despite accidental forces imparted to the knob or dial, for example, during transit or other handling. Others have attempted to create knobs that lock in place. U.S. Patent Application Publication No. 2009/0205461 A1 describes one such knob that requires a user to grasp the knob while imparting a secondary motion such as pulling or pushing in order to rotate the knob.